Variable capacitance non-contact AC voltage measurement system

A system to measure alternating current (AC) voltage in an insulated conductor, the system comprising:

• a conductive sensor positionable adjacent an insulated conductor without galvanically contacting the conductor, wherein the conductive sensor capacitively couples with the insulated conductor;
• a variable capacitance subsystem electrically coupled to the conductive sensor;
• a voltage measurement subsystem which in operation detects a voltage across the variable capacitance subsystem;
• at least one nontransitory processor-readable storage medium that stores at least one of processor-executable instructions or data;
• and
• at least one processor communicatively coupled to the at least one nontransitory processor-readable storage medium, and in operation, in response to execution of the processor-executable instructions or data, the at least one processor:
• causes the variable capacitance subsystem to have a first capacitance value (C1);
• detects, via the voltage measurement subsystem, a first voltage (VM1) across the variable capacitance subsystem when the conductive sensor is positioned adjacent the insulated conductor;
• causes the variable capacitance subsystem to have a second capacitance value (C2);
• detects, via the voltage measurement subsystem, a second voltage (VM2) across the variable capacitance subsystem when the conductive sensor is positioned adjacent the insulated conductor;
• and
• determines the AC voltage (VAC) in the insulated conductor based at least in part on the detected first voltage (VM1) and the detected second voltage (VM2).

A method of operating a system to measure alternating current (AC) voltage in an insulated conductor, the system comprising a conductive sensor positionable adjacent an insulated conductor without galvanically contacting the conductor, and a variable capacitance subsystem electrically coupled to the conductive sensor;

• the method comprising:
• causing, by at least one processor, the variable capacitance subsystem to have a first capacitance value (C1);
• detecting, by at least one processor, a first voltage (VM1) across the variable capacitance subsystem when the conductive sensor is positioned adjacent the insulated conductor;
• causing, by at least one processor, the variable capacitance subsystem to have a second capacitance value (C2);
• detecting, by at least one processor, a second voltage (VM2) across the variable capacitance subsystem when the conductive sensor is positioned adjacent the insulated conductor;
• and
• determining, by at least one processor, the AC voltage (VAC) in the insulated conductor based at least in part on the detected first voltage (VM1) and the detected second voltage (VM2).